This guide was mostly written near the end of Season 2. I have updated the Item Builds and Masteries sections and added a section about fighting Nami since the beginning of Season 3, and I plan on a larger update within the next few months.
Feel free to comment with any feedback you have regarding this guide.
This guide is a very long wall of text, but it's split up into sections so you can read only part of it if you want; unfortunately this means that a lot of it is redundant if you read the whole thing, but I figured it was worth it. Here's a table of contents:
(1) What runes should I run?
(2) What masteries should I run?
(3) What supports should you play Sona against?
(4) What ADCs should you play Sona against?
(5) What ADCs should you play Sona with, and why?
(6) What about meta-breaking botlanes?
(7) What items should I start on Sona?
(8) What items should I buy on Sona during laning?
(9) What items should I buy on Sona after laning?
(10) What to think about while laning as Sona.
(11) Power Chords.
(12) Auras. What do I keep persistent?
(13) My ultimate.
If you still have any questions about how to play Sona after reading this, let me know and I'll address them. My qualifications are that I have over 500 games played with Sona, a large percentage of which were with high-Elo (1800+) AD carries. I'm currently at 1700 Elo but don't really play ranked, and I've given several support lessons to people in the 1000-1500 Elo range.
(1) What runes should I run?
I like to run all flat tank runes. The reason for this is that I am trying to be strongest when my power is largest relative to the power of the other people in the game; or in other words, when I can have the biggest impact on the game. For Sona, this is very early on in lane. After level 6, Sona starts to fall off relative to other champions (not necessarily relative to other supports, but to item-building champions). She is very strong at level 1 with her auto + Q + power chord burst combo, she is very strong at level 2 with that damage and also a heal (or a slow if you don't need the heal to win), she is very strong at 3 and 5 as she gets more levels of her Q, and then her ultimate is amazing. A flash-ultimate can get you a kill with most ADCs against most botlanes. After this, Sona doesn't have farm to buy items to make her stronger, and so she starts to fall off. She also doesn't scale that well with damage items but continues to provide utility to her team the entire time she's alive, and so for this reason I like to build her as tanky as possible. So it's for these reasons that I prefer to not necessarily take GP10 runes and instead take armor yellows and flat HP quints, along with armor reds and MR blues. If the other three champions in the lane mean that Sona can't be as aggressive as you would like (for example if your ADC is a Vayne and you're fighting Corki-Leona), then consider running GP10 quints.
(2) What masteries should I run?
It's still unclear what the best masteries are in S3, but recently I've been running 0/9/21, making sure to take the 30 HP at level 1 in defense. In utility, I take the flash mastery, meditation, summoner spell and active item CDR, all 6 of the points to get the starting gold, three points in Strength of Spirit, and the biscuit and ward plus the 21st point in MS.
An alternative path is to remove the three points in Strength of Spirit and the 3% MS and to take instead both points in Unyielding, an extra point in the second row of defense, and Block, so that you have 0/13/17.
Where you put the 4 points in the second row of defense is up to you; I like to split them evenly, but ideally you would do it based on the lane that you're fighting, e.g. 3 points in MR vs Leona/Corki or 3 points in Armor vs Nunu/Cait.
You might notice that I do not take the exhaust mastery. This is because I think that the last points in both the 0/9/21 and the 0/13/17 paths are crucial to take. You might want to consider swapping exhaust and ignite with your ADC because it's more important to have the exhaust mastery than to have the ignite mastery; and furthermore, exhaust will help your ADC win duels with the enemy ADC when you're not there.
(3) What supports should I play Sona against?
Sona is an amazing choice against anything that can't 1-shot her. If your opponents are way worse than you then she's an amazing choice against anything (except Blitz), because her level 1 is so strong. In particular:
VS ALISTAR. Sona loses this matchup pretty hard, because she's not going to be able to get any poke down without being in Ali's engage range. If forced to lane vs an Alistar, I definitely recommend running GP10 and maybe even maxing W first because there's not much you're going to be able to do in lane; Alistar's ability to reposition you is too strong, and Alistar is pretty much the only support whose level 1 presence can rival Sona's. Unfortunately, Alistar is better lategame than Sona too (obviously depending slightly on teamcomp, I'd rather have Sona on a poke team, and potentially I'd rather have Sona on a full AoE team if the enemy doesn't have good divers that I need to peel for my ADC), so Sona just loses here. If you have to fight an Alistar in lane, you should probably pick Taric, Leona, Nunu, or Janna, whichever fits better into your overall teamcomp.
VS BLITZCRANK. This matchup is pretty much guaranteed to snowball one way or the other. If Blitz misses a hook, Q him and auto him for the next 15 seconds (don't assume he has 0 CDR) before backing off and waiting for him to have his hook up. If he gets to level 3 (so he has W, E, and grab), without you having a massive advantage already, then you have very little chance of being able to win the lane. I don't like playing this lane at all, and I won't pick Sona if Blitz is open (go for a melee support instead). If the level 1-2 doesn't go that well, then ward up very well and shove lane to turret all day. This will allow you to position behind your minions without causing your ADC to get zoned; it will also stop Blitz from camping a pink-warded bush. Make sure that you buy lots of wards (including pink wards) against a Blitz because the worst thing is to be pushed almost to your tower and not have your side bush warded. In this matchup, you have a few choices for runes, depending on what you're going to do with your ADC---if you're trying to win really hard when you're level 2 and they're level 1, AND THIS IS POSSIBLE BECAUSE YOU WILL GET GOLEMS AND SOFT-PUSH THE LANE 100% GUARANTEED, then run flat HP quints. Otherwise run MS (to dodge grabs) or GP10.
VS FIDDLE. I haven't played this lane very much. However, Fiddle is squishy enough that you should be able to poke him effectively early on, before his fear gets to be stupid long. You should probably have your ADC run cleanse in this lane, unless you're confident you can win lane decisively before about level 5, when Fiddle has 3 levels in Fear. Fiddle is a great support against whom you can try to get an early level 2 (take doubles or deny their doubles and soft-push the lane) and then try to push them out of lane or get a kill before they are level 2. As he gets more points in his Fear, the lane gets harder and harder. Once both sides of the lane are level 6, make sure that if you burn your ulti, you are DEFINITELY going to be able to get a kill because your ult is probably the only thing that can stop a Fid's channel, and you don't really want him to be able to ult you. When he is 6, make sure you have vision of him at all times, unless he's already so weak as to be useless because you won your lane so hard at levels 1-5. Remember to split away from your creeps and ADC if he casts his E on you so that you take less damage. Also make sure that you don't walk up to him for an auto+Q+PC combo when his E is up because he will be able to silence you before you can Q and then you'll lose the damage trade. I would consider running flat MR quints in this lane, but flat HP is always fine. If your carry is significantly more late-game than theirs, then GP10 is fine too, but keep in mind that the weaker your ADC is in lane, the stronger you should try to be to make up for it. Level QWQ and then take E if you're winning lane, W if you're losing.
VS JANNA. You win this matchup pretty convincingly. It's a long time before your power chord doesn't break through her shield, and your auto-Q-powerchord combo eats through her health. Both you and your ADC need to be very pokey in this lane, because Janna is actually better than you aside from her lack of sustain, and so you need to be dealing damage to them over time. Don't allin against a Janna unless they are already very low on HP, and if you allin on Janna once she's level 6, remember that she can always flash behind you and then ult you completely out of position. The best way to lose lane to a Janna is to allin her, underestimating her CC and shield power. If she burns her tornado for no reason, and it's before 6, then you're probably fine allining against her, but you should actually count her shield cooldown to make sure you don't get baited. Leveling Q and W without taking a point in E is good in this lane because you're not going to be able to chase down the Janna anyway, and since you're unlikely to be allining, being able to switch to the correct power chord within a single rotation isn't as important. Just get better sustain. However, if they have a jungler without a gap closer who's camping you, then take a level in E. If you decide suddenly at level 5 that you should have taken a level in E at 4, go ahead and sacrifice the level of Q---anything to keep you alive. I would consider running HP regen quints in this matchup even after the nerf because Janna won't have that much kill potential, but it depends on the ADC. Flat HP and GP10 are both fine too. This is one of the only matchups where it might be worth it to run flat AD reds instead of armor reds, because you really are just trying to poke all day.
VS LEONA. This matchup is pretty bad for you. Try to avoid it. If you have to play it, try as hard as you can to get level 2 first because when you're 2 and Leona's 1, you're way stronger---just don't get baited by their level-up if you try to allin. Run flat HP quints and ward Leona's bush (facechecking a Leona is REALLY REALLY BAD) and then auto-attack her and Q her and autoattack her more. You and your carry need to be really aggressive at level 1 and then allin at level 2 or you'll be stuck playing a passive lane where you don't have much presence at all. Note that if you are being aggressive like this, (a) WARD RIVER EVEN IF YOU DON'T EXPECT A GANK and (b) MAKE SURE YOU ARE ON THE SAME PAGE AS YOUR ADC. Leona can't split you from your carry the way that Ali and Blitz can, but if you are doing the splitting yourself for them, then it's only about 100 range between good aggression where they're focusing the support allowing your carry to clean up and you being out of position and dying for free. Don't underestimate Leona, though. Even if you're 2-4 kills up on them, it's still likely that they can engage on you, exhaust your ADC, CC you, and 1shot you before the CC is up. If you start winning (snowballing) this lane early, consider rushing an aegis without even buying GP10. Probably you should get a level of E at 4 just for faster traveling around the map and avoiding the jungler and getting a faster W chord off on their ADC in the event that you do get engaged on. Also Leona doesn't have any poke at all, so you shouldn't need to be healing that much.
VS LULU. She outtrades you when your combo isn't up, you outtrade her when it is. If she puts an E on you, try to walk so it's hard for her to get a Q off on your ADC. This is a matchup that I can't say that much about because it depends more on the ADCs than other support matchups do, since you and Lulu are so similar. Against a Lulu, I'd suggest still running HP regen quints, since she doesn't have much kill potential early but she does have a lot of harass potential. You probably don't want to get an early level of E unless you are snowballing, because Lulu is almost as hard to chase as Janna, so just win the poke war harder by having even more sustain.
VS LUX. Lux has very very good zone control with her E. You probably won't be able to hold bushes against her, so don't try. Her cooldowns are long, though, so if she misses a skillshot, then punish her for it. She has no sustain at all, so punishing her is actually really effective. You are way stronger than she is at level 1, especially if you are running flat HP quints, so try to be aggressive as possible at level 1 (again, ward the river). This is also a lane that it's fairly important to achieve level 2 first. In particular, Lux has 0 mobility, so it wouldn't be unreasonable to get E at level 2, get a slow chord off on her, and then try to kill her. She's really squishy, and a lot of Lux supports try to run flat AP---punish them for that.
VS NAMI. Due to Nami's release being very recent, I haven't had a chance to play this matchup much. If Nami hits her Qs on your ADC you lose, but if she doesn't then I think you win. It's extremely important that you pay attention to Nami's cooldowns in this matchup. If you see her heal her ADC, go aggressive. If she puts her E on herself or on her ADC, back up a bit until the E has expired. You would lose this matchup 100% except for the fact that Nami's mana costs are even more punishing than Sona's, so you can try to win the sustain game. Allining vs a Nami is definitely not recommended, because pretty much the only time she can guarantee a Q to hit is when you/your ADC are being aggressive. If she misses a Q, however, then you have a very long window of opportunity to be aggressive, since her Q cooldown starts so high. If she maxes her Q, then the cooldown will scale down very favorably, but then you'll be able to win damage exchanges with her because her W will be so weak (assuming you can dodge her Q---don't be predictable!!!) so you should be fine.
VS NIDALEE. Dodge her spears. Dodge her spears. Dodge her spears. Make 100% sure that you have her bush warded so that it's easier to dodge her spears. If you can't dodge a spear then walk towards it. The worst thing to do is walk away from a spear and not dodge it. For the first few levels, you absolutely wreck her, and then after that you win exactly when you dodge most of her spears. Get early boots (even with the nerf) so that it's easier to dodge her spears, and get an early level of E so that it's easier to dodge her spears. You just have to dodge her spears. Against a Nidalee, run HP quints if you think you can win an allin at level 1 (remember to ward river!), otherwise HP regen or MR or GP10. And remember to dodge her spears.
VS NUNU. If you don't win this lane really really hard, you lost it because BB is so much better than basically anything you can provide lategame (unless it's an AoE comp). If he ice blasts you, your carry should immediately try to trade; if he doesn't ice blast you, then you get free poke on him. DO NOT push against a Nunu; his ADC just wants to be farming under tower anyway. Yes, Sona automatically pushes with her Q, so think about not Qing as much and instead just harassing with your autoattacks, standing behind their creeps. WARD RIVER AND TRI IF YOU ARE STANDING THIS FAR FORWARD. I lose lane a lot because I don't feel like giving up my dominant position to ward. Don't do this. In particular, it may be worth it to reward as much as 30 seconds early so that you don't have to give up your dominant lane position to reward later (this holds in general, not just against Nunu).
VS SORAKA. Soraka is an annoying bitch, and I wish that she didn't exist in League of Legends even though I used to main her. Try to lane with Trist/Varus/MF against Raka so that you can get a free healing debuff, and try to zone them as much as possible at early levels. Time her W CD, and go for an allin when it's down. She is stupid weak at levels 1 and 2 unless she opened Q, so do a lot of harass damage to her then. If she gives her carry mana, take a more dominant lane position for the next 8ish seconds (don't want to underestimate her CDR). When her E is up she actually outtrades you unless you're already at 3 stacks of your passive. For this reason, you don't actually want to be comboing her very much (unless her E is down); instead just get power chords off on her. If she heals herself, you should allin on her carry if at all possible. Against a Raka take E if and only if you are dominating lane---otherwise it's too hard to get kills because her heal is dumb. However, Raka isn't that great late game so you should be fine on that front. Jungle ganks are good. Don't get heal baited if you try to dive her. Run GP10 quints against a Raka.
VS TARIC. At level 1, you absolutely dominate. At level 2, if he was forced to take heal because you won level 1 so hard, you still absolutely dominate. Once he has shatter, it's pretty scary. I wouldn't pick Sona into Taric, but it's not the worst possible matchup. Once he is 6, you have to be really careful, because his E-Flash-R-W is a huge amount of damage, and then adding the ADC's burst on top of that...you're probably dead. Rush a red crystal against him, and run tank quints, or you'll be forced to play very passive. Get a level of E at 4 if you're winning really hard, otherwise only get Q and W.
VS ZYRA. This is another matchup that I haven't played much, but I have played some support Zyra, and my conclusion is that Zyra is pretty good against Sona because of her excellent zone control, but that if Sona runs flat HP she should be able to get such a significant advantage at levels 1 and 2 that Zyra won't be able to win. This is another lane where getting early jungle pressure is extremely important for you because the lane can easily snowball in either direction. Don't run from Zyra's plants; kill them instead. Get E at 4 in this matchup if and only if you're winning really hard early; otherwise just try to sustain more. Since Zyra has no sustain of her own, as long as you don't die you should be fine. Buy a lot of HP pots. If you're having a hard time dodging her snares, buy boots early, otherwise get a fast red crystal and then chalice second so you can outsustain her even harder. If Zyra opens with a pink ward, try to push your lane pretty hard because if she gets control of her own bush that's very bad for you---there is no way for you to keep vision of your bush away from her completely because of her seeds (which she'll probably be maxing second), so she'll be able to poke you with Q, E, plants for free and you won't be able to do anything back to her. The advantage for you is that you're faster than she is, so it's easier for you to get auto attacks off on her.
(4) What ADCs should I play Sona against?
This section is much easier. Sona is good against short-range and late-game ADCs and bad against long-range ADCs.
VS ASHE. You can only walk up to her when her W is down, so time this. It's hard for you to trade with Ashe because your range is so much slower, but if she Ws and doesn't hit you or if her W is down you should definitely be able to get a combo off on her.
VS CAITLYN. This is my second least-favorite ADC to lane Sona against. Cait's zone control is amazing, and so Sona can't walk into good positions for Qs, and Cait's AA range is so long that Sona can't really poke her that well. You have to either play passive or have jungler camp lane or lane with an ADC with good enough engage and burst that there's always the threat of you flashing on top of Cait for lots of damage and your ADC gap-closing onto Cait with really good burst and ignite...like Ezreal.
VS DRAVEN. Just don't die. This is my least-favorite ADC to lane Sona against (but Sona is a pretty good choice against Draven if you trust your ADC and can hit 2 first; otherwise Taric is a better choice, or Leona). Cait is a pretty good choice for ADC vs Draven because of her range.
VS EZREAL. He pokes a lot; dodge his Qs and you will win lane, don't dodge his Qs and you probably won't. Sona is particularly good against Ezreal because he can't dodge her damage the way he can may other supports'.
VS GRAVES. He's really short-range, so you should be able to get a lot of harass off on him, just don't get Q'd in the face.
VS KOGMAW. This is another lane where if you don't win it really hard early, you probably lost it. Try to poke him as much as possible, and have boots before he's 6. Back off when he turns his W on, go in when it's on CD. Ideally he shouldn't be able to get a single CS with his W down without taking AA damage from you.
VS MF. She trades really really well. Don't stand behind your creeps when she's at full mana or she will be able to Q you (also try really hard not to play vs Blitz MF). Try to get combos off on her when you can, remember her W will stop your W from being effective, and don't waste your ulti without being able to convert a kill once she's 6. If you get her passive off, try to keep it off if possible. Buy a lot of HP pots vs her.
VS SIVIR. Remember Qing her gives her free mana, so don't do it unless you are trying to have her spellshield be down for some reason (or if you're trying to make it so that she doesn't equate you Qing her with your jungler being about to gank). Her Q hurts a LOT if you're the only target, so don't let that happen. Stand in the middle of your minions and AA her; her AA range is pretty short so you should be able to get a lot of AA damage off on her. Also note that your power chord counts as a spell for her shield.
VS TWITCH. He is INCREDIBLY squishy. Do as much damage to him early as you can. Buy a pink ward so he can't escape by stealthing. His damage output is huge, though. Try to dodge his W and don't forget about his expunge when you're calculating how much longer you can fight for.
VS URGOT. Urgot is really weak right now, dodge his stuff and attack him whenever he goes up for a lasthit. Beware his ult into a jungle gank at level 6.
VS VARUS. You won't really be able to trade with him unless you and your ADC are trading together. Try not to group for his ulti, try to get jungle ganks because he doesn't have mobility.
VS VAYNE. You NEED to shut her down. You do massive damage to her early, and before she has silver bolts she can't hurt you very much at all. Just make sure you're not against a wall that she can condemn you into. Your poke should be enough to zone her very effectively for a long time, but once she has any item at all you can't trade with her anymore. Have a pink ward for her ulti when she's 6, and try to get jungle pressure. You should definitely be trying to snowball lane against Vayne.
(5) What ADCs should I play Sona with, and why?
Sona is fine with every single ADC. Some ADCs are a kill lane at 6, some are poke lanes, and some you're just trying to keep them alive by being a scary threat in lane so that the enemy can't allin on you.
WITH ASHE. You are trying to get a kill at 6 by having Ashe ult and then Sona flash+ult. Poke with Ashe W before that. Sona doesn't need E because Ashe has W and Q.
WITH CAITLYN. This lane is so stupid to lane against. Cait can ensure Sona's bush control by placing traps, and Cait's range combined with Sona's poke means you can zone pretty much anything while Cait is still able to CS.
WITH DRAVEN. Run them down and kill them at level 2. Draven is stupid strong in lane, and adding Sona's damage to that is amazing. This is a lane where you're trying really hard to get level 2 first.
WITH EZREAL. This is still my favorite lane to play because it's just so fun. Both of you have amazing poke, and if Ezreal buys a couple mana pots you have enough sustain to kick them out of lane for daring to try to get a couple CS.
WITH GRAVES. Massive damage from Graves Q (if he's close to the enemy) and Sona Q. Massive burst at 6 from their combined ults. This is one where you exhaust the carry, ult and burst the support at 6.
WITH KOGMAW. Don't go for kills early, but once Kogmaw has an item you should be able to run a lot of things down and kill them. Get a level of E by 7 (yes, worth it to sacrifice Q if you didn't get E at 4) so that you can help slow them. It's not as good as Kog-Nunu for running people down, but it's still decent with your E chord and Kog's E. Remember that Kog's damage isn't that high in lane so you shouldn't be trying to allin early, but you can definitely be harassing.
WITH MF. Poke them and trade with them all day. This lane is also really strong with the poke from MF Q and your Q. Get your E at level 4 so that MF doesn't need to burn mana on her E for the slow to chase them down (or possibly not even take her E at all). This is a lane where it can be really tempting to push all day, but you shouldn't; actually just zone them if possible. You have pretty decent kill potential at 6 with your ults combined, as long as you've been maintaining your poke the whole way so that they're already low.
WITH SIVIR. Really good poke, really good bush control (Sivir should be able to get a full Q off on their support if he dares to step in the bush). Not a good allin, but you have an amazing trade potential at 6, so you can fight anything that's not a kill-at-6 lane once you get 6. This lane is very good for zoning due to Sivir's Q damage when minions aren't in the way combined with your combo damage.
WITH TWITCH. Amazing damage. Get them to think that Twitch is out of lane (take a few CS yourself), have him stealth in an unwarded bush, and then kill them; he'll slow them with W and you can slow with an E chord and you should be able to do at least 50% of their health if not kill them completely.
WITH URGOT. I don't really think you should play this lane. But with jungle pressure at 6 you can get a good combo of your ult plus Urgot's ult, and prior to that you have a lot of poke damage if Urgot can hit all his missiles.
WITH VARUS. Good poke lane that's also good at securing a kill at 6 by chaining your ult plus his. This is one where you'll probably have to lead with a flash-ulti and then have him follow up because yours is way easier to hit.
WITH VAYNE. Just keep her alive to lategame until she has her first item, then you can try to fight them. Probably don't get a level in E because you really don't have that much kill potential early. Unless it snowballs for a bizarre reason at 1 or 2.
(6) What about meta-breaking botlanes?
Something like Leona-Panth, Leona-J4, Blitzstar, etc. that is just there to kill you, you should play very safe. You can level W first if need be. Just don't die. They will snowball backwards if they don't get any kills, so just rush tank items, keep brushes warded, and don't worry about getting gp10s---if you don't have your philo until 20 minutes and that's your only gp10 but they didn't get a single kill then you won.
(7) What items should I start on Sona?
There are a lot of options for this now, and it depends entirely on the lane you're fighting.
CLOTH ARMOR---If it's a double-bruiser botlane or Nunu/Cait or Ashe/Janna then I would consider getting a cloth armor, 2 wards, and 2 potions, probably one mana and one HP. The reason for this is that vs the double bruiser lane, you really need the extra survivability, and vs the carry/support lanes mentioned, you're trying to allin very early so the extra tankiness is worth it at the expense of the superior mana sustain of Faerie charm.
FLASK---I tried this for a while and decided that I don't like it that much. But it can be viable to trade very aggressively early if you start with a flask and several wards and a few pots. I wouldn't recommend starting with only flask + wards, even with the biscuit, simply because if you start out with three wards you're unlikely to need to base because you need additional wards first; you will probably base earlier than that because you got a kill or are low on health/mana resources, due to Sona's aggressive nature in lane.
REJUVENATION BEAD---I don't think this is a good opening item; I would rather have the Faerie charm. But you can consider this if you're planning on playing passively after level 2, e.g. vs a Leona. You would get three sight wards and three potions (HP or mana, your choice) in addition to this item.
FAERIE CHARM---This is still my preferred opening item on Sona (actually, on pretty much every ranged support). Faerie charm, 3 wards, 2 HP pots, and 1 mana pot.
BOOTS---Not really worth it at all anymore as an opening item on Sona.
ONLY WARDS AND POTS---You can still do this if you are going to do a coordinated level 1 fight with your team. Otherwise get at least a flask.
OTHER---Situationally, you could open with a red crystal or a null-magic mantle, but you would only do something like that if you have a definite plan for a level 1 fight or something.
(8) What items should I buy on Sona during laning?
SUGGESTED. Faerie Charm --> Red Crystal --> Cloth Armor --> Chalice --> Emblem --> Laning over/get boots now.
RED CRYSTAL. This is almost always the first thing to buy. The extra HP is just too good to get pretty much anything else, assuming you're playing very aggressively.
MANA MANIPULATOR AND EMBLEM. These two items are both extremely good in lane, especially if you're playing a sustain-poke lane with an ADC with high mana costs. I would definitely consider getting both of these two items in lane if I notice my ADC running out of mana a lot.
GP10. Both Kages and Philostone build into good support items, with Shurelyas still being an amazing support item. You would build Kages into Twin Shadows or Shard of True Ice. Shard is nice because it also gives you the mana regen aura of mana manipulator, but I don't think it's that good of an item relative to its cost. You can build GP10s if you're playing somewhat passively and not at huge risk of dying, but otherwise I wouldn't really get GP10s anymore.
SIGHTSTONE. I think this can be an okay item at the end of laning, but I would never ever get it during laning---when you first buy it, you're spending 700 gold all at once to get 100 HP and 2 wards basically, since you're unlikely to stay in lane so long that your wards expire. Compare this to spending 625 gold on 180 HP and 2 wards. That 80 HP is actually a lot on Sona early on, and keep in mind that you're unlikely to have as much as 700 gold on your first back---in fact, I usually ask my ADC to buy a ward for me, since I usually only have about enough for a red crystal and a single ward. Every time you go back to base, the money could be spent on snowballing your lane forward even harder and I don't think it's a good idea to get a sightstone instead. If your opponents build efficiently during lane they will just be able to beat you.
BOOTS. I don't really get boots on support until after laning is over with the new boots nerf.
CHALICE. I consider this to be a laning item on Sona. The ability to spam your spells is HUGE; the sustain and trading power you get from constant Qs and Ws is great, and in addition you can get power chords up way more often. Chalice means that you can start a fight out at about 50% mana and regen enough during the fight to be able to cast spells through most of it. Furthermore, chalice now builds into Mikael's Crucible, which is a fantastic item.
KINDLEGEM. This has always been a great item and is still a great item. Both Shurelyas and Locket are very good items, so you can build it into either, depending on what your team needs. I wouldn't necessarily get one in lane anymore (on Sona) because I think there are better choices, but if you feel you really need the CDR (e.g. you are getting ganked more often than your ult cooldown) then go for it.
(9) What items should I buy on Sona after laning?
There isn't really anything special about Sona vs other ranged supports in terms of late-game items, but make absolutely sure you have a chalice by 30 minutes at the latest. Good items right now are Aegis, Shurelyas, Mikael's, and Locket pretty much always; and Twin Shadows and Shard situationally. If either (a) your jungler and toplane both have a Sightstone or (b) you have an item slot to spare, by all means get a Ruby Sightstone; it's a very good item for three people on your team to have, since 9 wards at a time on the map is pretty much sufficient. However if you're the only person buying wards and you don't have two item slots free for wards plus an item slot for pink wards, I don't actually recommend getting a Sightstone, since 3 wards at a time is NOT enough. You will definitely need to have two slots dedicated to wards (sightstone + a stack of 5) and also a slot for pink wards, leaving you with a slot for boots and two other slots, which is not really going to be enough.
For boots, you can do cooldown if you're not getting focused AT ALL in fights, merc treads if there's a lot of AoE CC that you want to be able to escape quickly (the most notable one being Galio ult, so that you can cancel it early with yours after your taunt ends, or anything with a Crucible so that you can cleanse your ADC), or tabi otherwise. For enchantments, I recommend Captain or Distortion or maybe Alacrity, but I think that your boots enchantment should be the last thing that you buy.
Get Oracles whenever there's a Baron dance; otherwise just use pink wards.
(10) What to think about while laning as Sona
Think of your lane and the enemy's lane as having sets of different resources. These resources include gold (to be spent on items later), HP, mana, map vision, and lane positioning. Ideally you're trying to exchange the latter resources for the first one---you want to sacrifice some of your mana so that you can force them into a lane position that doesn't allow them to get gold, or you want to sacrifice some of your HP for all of their HP, so that you can get gold for items later, etc. Most people already think of HP and mana as resources to be managed, but it's important to remember that map vision and lane positioning are also resources. You frequently trade lane positioning for HP and mana or HP and mana for lane positioning, and when deciding where (and when!) to place your wards, you trade between map vision and lane positioning. For example, it would be great to have a ward in toplane or at their red at the beginning of the game for extra map vision, but can you sacrifice the lane positioning that you'll lose from not being able to ward the enemy support's bush twice? Do you want to sacrifice the map vision that you could get from a ward for an extra two HP pots? And do you want to spend gold on map vision? Obviously you want to have some wards on the map. But if you're blue and you have dragon warded and your mid warded your wraiths, do you really want to spend the gold on a tribush ward?
These questions are important to think about with every support. Sona in particular usually wants to be sacrificing a lot of things for early lane positioning---you sacrifice gold for HP pots and mana pots, and you sacrifice mana for HP, and you sacrifice some HP for lane positioning. THIS DOES NOT MEAN RUN UP TO THEM UNSAFELY. "Will this make me die?" is a question you need to ask yourself whenever you do anything, and if the answer is yes, and you're not going to get kills or objectives, DON'T DO IT. But if it's safe to do, you should try to position more dominantly. Knowing when it's safe to run up and Q the enemy ADC is something that comes with practice. When you're at a full mana bar, run up, auto+Q+powerchord or just auto+Q the enemy ADC and then immediately W so that any damage that you take in return is diminished by your extra armor and MR.
As your mana starts to run out, make sure that you have enough for 4 spells and an ult so that you're unlikely to run oom during a fight, and start to back off a bit. You need to exchange some lane positioning for mana, which will allow you to increase your HP resource and drain their HP resource. This does NOT mean stand way behind your ADC. It means you stand as far forward as you feel comfortable standing given that you don't have mana to spend on Q+W immediately for a trade. This is a good time for a jungle gank if the lane is pushed to a good point, since you have enough mana for a fight right now but no more. It's also a good time to start thinking about going back to base, if the lane is pushed and your ADC has a good amount of money to spend. ('good' isn't the same as 'a lot'---for example, 1550 gold is a really bad amount to base with if he already has two dblades, vamp scepter, and boots 2 and wants a BF sword rather than a zeal)
(11) Power Chords
This is basically the reason Sona is a god. After casting three auras, your next attack will do additional damage and also have a secondary effect depending on the most recent spell you cast. Q will double normal damage, W will apply a debuff to the target that causes them to deal 20% less damage for the next 4 seconds, and E will slow them by 40% for 2 seconds. Power chord (bonus) damage is 8 + (10 x level) magic damage.
The first thing is how to manage your power chord at the beginning of the game. If you're going to be attacking jungle camps (helping jungler with wolves/blue or taking doubles with your ADC) then you want to start out with all three stacks, so Q once, buy items, Q a second time as you're leaving well, and then Q a third time around 1:30 so that you have 3 stacks when you're starting the camp but 2 stacks for as long as possible in case there's a fight. Use your power chord on the camp immediately, wait about half a second (otherwise it can bug and not give you your first stack even though you cast your Q after discharging your chord), Q once, then Q again, then just autoattack so that you're at 2 stacks for lane. If you're helping your jungler then the first Q is on wolves and the second is on blue (try to make it so that you Q blue and a small minion instead of the two small minions). If you're taking doubles, then Q for the second time on cooldown. I suggest giving the small golem to the support and big one to the ADC so that both of you hit 2 early, but the ADC gets the extra gold. Or just make sure that you're in melee range of the golems when they die, but this is hard to do without taking too much damage.
If you're not attacking jungle camps, just keep your passive at two stacks for lane. You'll go into lane, ward the side bush, and then try to combo the support; if the enemy ADC and support aren't in lane yet, and they're not something that's especially strong at level 1, then walk up with your ADC so that you can get a combo off on them when they get into lane plus damage from your ADC. Make sure that you're not scared of a quick level 2 gank from the jungler though. I like to ward river/tri very early if I'm blue and their jungle started blue or purple and their jungle started red as Sona so that this very early aggression is safe. However, do make sure that you're on the same page as your ADC. If your ADC is back and you're trying to run up at level 1, you're out of position. Don't do it.
Once you are level 2 and have more power chords, it becomes more complicated. You're about to all-in their ADC. Should you open with a W chord or a Q chord? If you're both level 2, a Q chord is probably going to be more damage on them than a W chord will prevent, but as the game progresses it becomes more important to get the W chord off before the enemy lays down their burst, as fights last for longer. I could give you a large table of numbers, but honestly, this is something you won't have time to calculate nor is it something that's practical to memorize. Just try doing both and develop a strong heuristic. Generally in early lane a Q chord is better.
You're about to poke their ADC and you have an E chord ready. Should you use it immediately and then follow with a Q and another auto? Or should you Q and then auto so that you get the extra power chord damage? Again, this depends on a few factors. If your ADC will be able to get in an auto also but only if you use an E chord, go for the E chord. If you're hitting them with power chords each time you get one up, go for the E chord so that the Q also gives you another power chord stack. If you're at full mana and can chase a bit, go for E chord followed by E --> W --> Q --> another power chord with an autoattack as soon as your AA cooldown comes up after the first E chord.
You're chasing an enemy and at 0 or 1 stacks. DON'T USE YOUR E IMMEDIATELY. This is so important. Sure, you are out of Q range and your teammates are at full health. Cast a Q and a W before your E (or just one of them if you're already at 1 stack) so that you get your power chord up.
It's a teamfight and there's a bruiser on your ADC. Any one of the three chords could be appropriate. If the bruiser is about to die and doesn't have much MR, go for a Q chord to try and get the kill faster. If it's Udyr or someone else who's kitable, go for an E chord. Otherwise go for a W chord since the fight will probably last for a long time and the reduced damage from the bruiser is almost certain to pay off.
It's a teamfight and you're in AA range of the enemy ADC. Try to get a W chord off. However, it's a good idea to try to not stack your exhaust with your W chord, so exhaust and then IF THERE ISN'T A GOOD SECONDARY TARGET FOR YOUR W CHORD hold your auto for the exhaust to run out; then W chord the ADC. What is a good secondary target for your W chord? A bruiser or a mage WHO STILL HAS COOLDOWNS UP. Don't W-chord the Lux who already ulted, Q'd, and E'd that fight, but do W chord the Orianna who ulted but is about to move her ball. Try not to W-chord the enemy support.
(12) Auras. What do I keep persistent?
The one that you have leveled the most, usually. Don't keep your level 1 W aura persistent when you have a level 4 Q aura. However, there are many specific circumstances under which you should do specific things.
Your ADC/team is/are CC'd. Keep your W aura up until they are ready to deal damage, and then put up a Q aura.
You're running away. Keep your E aura up, and then slightly more than .5sec before it's about to come up, W and then E again (or Q and then E again, if the people chasing you are low). This way you never lose the passive MS and gain the active MS as frequently as possible, but you are still able to heal your teammate and yourself.
You're fighting with a mage. Use Q and then W when their cooldowns are used; then Q again when their cooldowns are about to come up. This is more relevant to someone with long cooldowns like Lux or Brand than it is to someone like Ori or Zyra with short cooldowns, and it's not at all relevant to Cassi or Karthus with virtually no cooldowns.
You have a kiting comp. Keep your E persistent during the teamfight provided it's high enough level (around 3 or 4 probably).
They have an AoE comp. Start with your W aura and switch to Q after their AoE is used up. Similar if you're trying to mitigate damage from someone's burst. For example, if Mummy is mid-bandage toss to your team, your instinct may be to Q him, but you should actually turn on your W aura before he can ult. Especially if he's building AP.
You're stomping them. Just keep Q aura up.
You're taking baron/dragon and you have someone able to tank it easily. Keep Q persistent; when the cooldown is about .5 seconds from coming back up, W once and then return to Q---or, if mana really isn't a problem, E then W then Q starting exactly a second before Q is about to come up so that you can Q on cd and get another power chord.
You're taking baron/dragon and you don't have someone able to tank it easily. You want to be Q-chording it on cooldown but keeping your W aura persistent (if possible given mana limitations). Figure out how to do that based on current number of stacks of power chord; remember getting a power chord resets your AA animation.
In lane, if you're taking a lot of poke, keep W persistent, especially if you didn't take E at 4. If you're not taking much poke, keep Q persistent. If you need to be dodging important skillshots like Nid spears or Blitz hooks then keep E persistent. The default should be to keep Q persistent because (a) it's the one that you're leveling the most and therefore the most efficient in a neutral situation and (b) it will help your ADC lasthit more effectively.
(13) My ultimate.
This is what most people think of when they think of Sona. You use your ult for different purposes depending on teamcomps. If you're fighting something with an important-to-break channel (e.g. Katarina or Galio), and you don't have very much CC to use to stop that ultimate, then your teamcomp is probably bad compared to theirs; but you should try to save your ult to break that channel, unless you have one thousand percent confirmed with your (for example) Garen that he will ONLY use his Q to interrupt the Kat ult and will flash to do so if necessary in which case you should use your ult to initiate. If you have a Galio or an Amumu or something similar on your team with very good AoE CC also, then you should decide who's going to initiate and then CHAIN YOUR CC WITH THEIRS. That does NOT mean ult at the same time as Galio ults; it means ult when his ult is about to expire or the instant that somoeone breaks his channel.
In lane, try to hit both the ADC and the support with your ult. If you can't do that, it's frequently better to ult the support, exhaust the ADC, and then kill the support before the stun wears off---why? Because the support is typically better at saving people's lives than the ADC is. You don't want Lulu to be able to ult or Soraka to be able to heal or Janna to be able to tornado and shield and W and ult. Remember though that your ADC can be exhausted by a stunned support, so make sure that you won't be baited if their exhaust is up.